The WinXP guest seems to work fine with the timer resolution, accuracy and latency of qemu. The problem with linux guests might be related to this issue. I will test the ehci emulation without the specified kernel config and see how can we handle timing issues in a more qemu-oriented way. Any tip?
Arnon -----Original Message----- From: Paul Brook [mailto:[EMAIL PROTECTED] Sent: Tuesday, January 08, 2008 3:30 AM To: qemu-devel@nongnu.org Cc: Arnon Gilboa; KVM; Roni Luxenberg Subject: Re: [Qemu-devel] [PATCH] USB 2.0 EHCI emulation > -The host kernel was configured with dynamic tick & hi-res timers, to > allow the desired timer resolution. USB 2.0 microframe is 125usec. Requiring a 8kHz timer is a non-starter. The 100kHz "retry" timer is even more bogus. Qemu isn't capable of this kind of realtime response. You need to figure out an implementation that doesn't require extremely fine grained timers. In paractice you're unlikely to get better than 10ms timer resolution, and 100ms latency isn't that uncommon. Paul
